Revealing the silver and nickel doping action for enhancing the adsorption selectivity of nitrous oxide and carbon dioxide on biomass porous carbon

The intensification of global climate change has heightened requirements for efficient, economical and sustainable technologies aimed at reducing greenhouse gas emissions. Carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) have become crucial objects for urgent treatment due to its high global warming potential and involvement in ozone layer destruction. In this study, transition metal silver (Ag) and nickel (Ni) doping on porous carbon materials with exceptional adsorption selectivity performance in N 2 O/CO 2 mixed gas were prepared by utilizing eucalyptus bark as the precursor, and the experiments and mechanism of N 2 O adsorption selectivity promoted by Ag and Ni doped transition metal were systematically explored. The results showed that the adsorption performance of Ag-doped sample was greater than that of Ni-doped sample. Among them, the existence of Ag 0 within the sample of 3EPC-Ag achieved the highest of 0.88 at.%, which brought the maximum N 2 O adsorption capacity of 2.13 mmol·g −1 , and the outstanding dynamic adsorption selectivity of 3.11 for N 2 O/CO 2 gas mixture at room temperature and pressure. Furthermore, characterization analysis demonstrated that the improvement of adsorption performance and selectivity was derived from the interaction between Ag 0 , Ni 2+ and N 2 O molecules, respectively, especially the effect of Ag 0 , which was approximately 1.5 times that of Ni 2+ impact. Subsequently, theoretical calculation also indicates that Ag 0 possessed a high binding energy for N 2 O, and considerably strengthened the selective adsorption of N 2 O via coordination bonding and induced polarization effects, which is consistent with the experimental test. This achievement proposes an available route of synergistic effect of low-cost biomass and metal post-doping, featuring a convenient and sustainable design process for efficient N 2 O adsorption and separation of N 2 O/CO 2 .